The BIST 100 index on the Istanbul Stock Exchange started the week with a 0.24% decline at 10,481.45 points. At the opening, the BIST 100 index dropped by 25.65 points and 0.24% compared to the previous close, reaching 10,481.45 points. The banking index gained 0.06%, while the holding index increased by 0.45%. Among the sector indices, financial leasing factoring had the highest gain with 0.89%, while trade had the most significant loss with 3.16%. In the domestic market, the BIST 100 index, which followed a buying-weighted trend on Friday, closed the day with a 0.46% gain at 10,507.11 points. In global markets, concerns about U.S. President Donald Trump’s protectionist trade policies deepening trade wars and possibilities of slowing growth in the world’s largest economy, the U.S., are increasing risk perception. Additionally, it was decided that the Borsa Istanbul will implement the upward tick rule in short selling transactions in stocks included in the BIST 50 Index for one day in today’s session. Analysts noted that technically, the support levels for the BIST 100 index are at 10,350 and 10,300 points, with resistance levels at 10,550 and 10,650.